1. Field of the Invention
This invention relates to a method for the fabrication of a semiconductor device. More particularly, this invention relates to a method for the fabrication of a semiconductor device of the MOS (Metal Oxide Semiconductor) construction possessed of a gate oxide film excellent in dielectric strength.
2. Description of the Prior Art
The gate oxide film in the semiconductor device of the MOS construction is desired to have the smallest possible thickness and manifest a high dielectric strength uniformly. Various conditions have been proposed for the formation of a film oxide capable of producing a high dielectric strength and have accomplished the desire to some extent.
From the point of view of a silicon wafer substrate, however, since the question as to what kind of silicon substrate ought to be used to obtain successful formation of an ideal gate oxide film remains in the greater part yet to be elucidated, no noteworthy measure has existed to date except for the practice of preparing polished wafers of a prescribed thickness from an actually pulled semiconductor single crystal bar, producing MOS construction devices from the polished wafers, testing the devices for oxide film dielectric strength, selecting those having a dielectric breakdown voltage above a prescribed minimum as conforming samples, and putting the conforming products to use.